Sanding drum structure in a drum sander

ABSTRACT

A drum for use with the drum type sanding machine or drum sander which features a quick and ready replacement of a sanding surface member to and from the outer circumference of the drum. This drum is specifically equipped with a tubular air jacket which is adapted to entirely surround the drum outer circumference after onto which a suitable endless and seamless sanding surface member or sanding belt is placed so that a replacement of worn sanding belt with a new one may be performed simply and quickly by discharging compressed air filled up in the tubular air jacket disposed around the drum thereby to reduce the outer diameter of the drum and provide a sufficient gap between the drum and the sanding belt and by recharging compressed air into the air jacket thereby to fix the sanding belt rigidly in proper position for sanding operations.

Hasegawa 1 51 Nov. 19, 1974 1 SANDING DRUM STRUCTURE IN A DRUM SANDER[75] Inventor:

[73] Assignee: Meinan Machinery Works, Inc.,

Aichi-Pref., Japan 22 Filed: Dec. 29, 1972 21 Appl. No.: 319,728

Katsuji Hasegawa, Nagoya, Japan [30] Foreign Application Priority DataDec. 28, 1971 Japan 46-471288 52 US. 01. 51/373 51 1m. (:1 B24d 9/02[58] Field of Search 51/373; 242/72 B; 294/63, 294/86.24, 93

[56] References Cited UNITED STATES PATENTS 683,123 9/1901 Knill 51/3731,487,256 3/1924 Mall 51/373 2,113,836 4/1938 Hamilton 51/373 2,116,2725/1938 Mall 51/373 2,225,073 12/1940 Miller 51/373 2,448,884 9/1948Hamilton 51/373 4/1950 Mall 7/1957 51/373 Miller 51/373 PrimaryExaminer-Othell M. Simpson Attorney, Agent, or FirmWoodhams, Blanchardand Flynn [5 7] ABSTRACT A drum for use with the drum type sandingmachine or drum sander which features a quick and ready replacement of asanding surface member to and from the outer circumference of the drum.This drum is specifically equipped with a tubular air jacket which isadapted to entirely surround the drum outer circumference after ontowhich a suitable endless and seamless sanding surface member or sandingbelt is placed so that a replacement of worn sanding belt with a new onemay be performed simply and quickly by discharging'compressed air filledup in the tubular air jacket disposed around the drum thereby to reducethe outer diameter of the drum and provide a sufficient gap between thedrum and the sanding belt and by recharging compressed air into the airjacket thereby to fix the sanding belt rigidly in proper position forsanding operations.

9 Claims, 2 Drawing Figures I SANDING DRUM STRUCTURE IN A DRUM SANDERBACKGROUND OF THE INVENTION The present invention relates to the fieldof polishing machines, and particularly to a new and useful device whichis applicable to the drum type sanding apparatus or drum sander. Moreparticularly, this invention is concerned with a drum of unique designand construction adaptable to polishing or sanding operations, which isdesigned for use with the drum sander enabling a sanding surface memberor sanding belt to be easily fixed and detached to and from the drum.

This invention is intended for easy replacement of the sanding surfacematerial by means of a drum having a uniquely designed diameterreduction mechanism which permits a ready and quick replacement of thesanding surface material to and from the outer circumference of the drumfor a drum sander, thereby to afford efficient sanding operations.

In the conventional drum sander, it requires considerably awkward jobssuch as cutting a strip of the sanding surface material from a roll ofsame in an exact length corresponding to the outer circumference of thesanding drum and fixing the cut strip properly around the outercircumference of the drum without any gap between the cut ends of thestrip, thereby to attain a complete sanding surface installation on theouter circumference of the drum. Moreover, such toilsome jobs arerepeated at each time of replacement of the sanding surface member.

Furthermore, since there exists a seam between the abovementioned cutends of the sanding surface member on the outer circumference of thedrum, it is inevitable that such seam will give undesirable marks on thefinished surface of the product, and consequently, it is practicablyimpossible to obtain a clean scar-free finish on the surface of theproduct.

On the other hand, in case of the conventional wide belt sander using anendless belt, it is possible to eliminate the abovementioned defects andproblems encountered in the drum sander due to the use of the sheet typesanding material, thereby to result in satisfactory sanding operations.

Generally speaking, however, this type of machine has the followingdrawbacks, i.e., requirement for a plurality of rolls as well asspecific extra means for giving the belt proper tension or effectingautomatic running adjustments, despite its satisfactory sandingoperations. Therefore, there will be brought about such problems from aneconomical point of view, as an increase of production cost, intricateand toilsome maintenance services, etc. due to the complicatedconstruction thereof as compared with the drum sander which is simplyconstructed and handled.

SUMMARY OF THE INVENTION In consideration of the above stated defectsand problems which are inherent to the conventional design andconstruction of a sanding apparatus, either of the drum sander or thewide belt sander, it would be advantageous to provide a drum for usewith the drum type sanding apparatus of novel and unique design concept,which enables the outer diameter thereof to be reduced by means ofdeflatable air jacket incorporated under the circumference of the drumcomplete, for readily and quickly replacing an endless sanding surfacemember or sanding belt thereby to eliminate the abovementioned defectsand problems inherent to the sanding apparatus of the conventionaldesign and construction. This invention is directed essentially to meetsuch requirements which have long been left neglected.

It is therefore a primary object of the present invention to provide asanding drum for use with a drum sander incorporating a unique mechanismunder the circumference thereof which enables the outer diameter of thecomplete drum to be varied by means of an air jacket to be inflated bycompressed air therewithin, which does not require wearisome jobs ofcutting and adjusting the sanding strip but does perfonn ready and quickreplacement of the sanding surface member without any specificdifficulty. Another object of this invention is to provide a drum of theunique construction'using an endless sanding surface member or sandingbelt, which performs fixation of the sanding belt in an outstandinglyprecise order on the outer circumference of the complete drum. v

A further object of this invention is to provide a sanding drum for thedrum-sander affording the use of an endless and seamless sanding belt,which eliminates such apprehensions as of rendering undesirable marks ofa joint seam of the sanding member on 'the finished surface of theproduct.

According to the present invention, briefly summarized by way of'apreferred embodiment, there is provided a drum for use with the drumtype sanding apparatus which comprises a tubular air jacket disposed onthe outer circumference of the basic construction thereof, which airjacket is adapted to be deflated by discharging compressed air therefromand inflated by recharging compressed air thereto, and a layer ofresilient body disposed to flexibly surround the outer circumference ofthe air jacket, which layer of resilient body being adapted to assure apositive adhesion of the cylindrical sanding surface member duringsanding operations, thereby to afford the use of the seamless cylindrical sanding surface member in a detachable manner, whereby thesanding surface member may be replaced readily and quickly to precisionso required.

BRIEF DESCRIPTION OF THE DRAWING The nature, principle, and details ofthe present invention, as well as further characteristics and advantagesthereof, will become more apparent from the following detaileddescription with respect to a preferred embodiment of the invention whenread in conjunction with the accompanying drawing, in which like partsare designated by like reference numerals, and in which:

FIG. 1 is a side elevational view, partly in axial section, showing acomplete sanding drum according to this invention with compressed airdischarged from its air jacket to a deflated circumferential state; and

FIG. 2 is a side elevational view, partly in axial section, showing thesame complete sanding drum as shown in FIG. 1 with its air jacket filledup with compressed air for fixing a sanding surface member in operatingposition.

DETAILED DESCRIPTION Referring to FIGS. 1 and 2 showing a preferredembodiment of the drum for sanding operations according to the inventionfor use with a drum type sanding apparatus or drum sander, there .isprovided a cylindrical drum A which comprises the following compositemembers, i.e., a basic roll of rigid construction 2, an air jacket 1which is installed snugly around the outer circumference of the basicroll 2 and designed with an inflatable-and-deflatable construction bycharging or discharging compressed air, respectively, and a resilientbody 3 having an appropriate thickness such as sponge rubber or the likewhich is adapted to entirely coat the outer circumference of the airjacket 1.

In the abovementioned design and construction of the drum A, the rigidconstruction of the resilient body 3 onto the outer circumference of theair jacket 1 is to merely show one example thereof, and it may thereforebe detachably installed thereon.

The fundamental construction of the drum according to this invention isfully described hereinbefore, and onto the ultimate outer circumferenceof the thus constructed cylindrical drum A there is provided an endlessand seamless sanding surface member or sanding belt 4 to be installedproperly in position while the air jacket 1 is deflated by dischargingthe compressed air therefrom, thus a complete sanding drum arrangementis accomplished.

In applying to the abovementioned sanding drum according to thisinvention, the sanding belt 4 should necessarily be of an endless andseamless cylindrical construction which completely eliminates theaforementioned defects accompanying the conventional strip type ofsanding material.

As is apparent from FIG. 1, when compressed air is discharged from theair jacket 1, the outer diameter of the complete cylindrical drum A ismade appropriately smaller than the inner diameter of the sanding belt4, whereas, when the air jacket 1 is filled up with compressed airtherewithin, as shown in FIG. 2, the outer circumferenceof the completedrum A is properly inflated to an extent that the outer diameter of thecomplete drum A is increased enough to meet the inner diameter of thesanding belt 4 so that an entirely compensated fixation of the sandingbelt 4 on the outer circumference of the complete drum A is thusaccomplished. Therefore, quite an easy and quick replacement work ismade available by virtue of the abovementioned unique construction ofthe complete drum A as well as the use of the endless sanding belt 4.

As fully described hereinbefore, the advantageous features of theconstruction of the cylindrical sanding complete drum A will insure aneasy and quick replacement of the endless sanding belt 4, that is, whenthe sanding belt 4 is required to be replaced, compressed air within theair jacket 1 on the drum is firstly discharged, thereby the air jacketis deflated to reduce the outer diameter of the complete drum A, andthen a worn belt is replaced with a new one. This replacement work willbe conducted quite easily because there is no resistance to checkremoval of a sanding belt due to a substantial difference existingbetween the outer diameter of-the complete drum A and the inner diameterof the sanding belt 4.

Likewise, this is quite true with an installation of the sanding belt 4onto the outer circumference of the complete drum A. After installationof the sanding belt 4 in right position on the drum, the sanding belt 4will be firmly and precisely fixed in a predetermined position on thecomplete drum A simply by charging compressed air into the air jacket 1on the drum as the outer circumference of the resilient body 3 willprogressively grow radially outwardly when the air jacket 1 inflatesunder inner pressure therewithin so as to exactly reach and fit to theinner diameter of the sanding belt 4.

Consequently, by virtue of the use of the sanding drum according to thepresent invention, a replacement work of the sanding belt in thecylindrical form to and from the complete cylindrical drum A will beperformed remarkably readily an quickly, and further an installation ofthe sanding belt in a predetermined position on the drum will beaccomplished much more precisely without any particular difficulty whencompared with the use of the conventional sanding drum and surfacemember, whereby an efficient sanding operation is afforded.

Moreover, by virtue of the use of the endless and seamless sanding belt,such apprehensions of printing undesirable marks of the seam of theconventional sanding strip on the finished surface of the product, asstated hereinbefore, will entirely be eliminated, and consequently,there willv be provided quite a satisfactory finish free from scars onthe product surface.

Furthermore, the drum sander using the sanding drum according to theinvention does not require any such complicated construction as requiredin the conventional wide belt type installation using an endless belt,which requires, as also stated hereinbefore, complicated adjustments aswell as intricate and toilsome maintenance services during sandingoperations, consequently, resulting in remarkably economical advantagesfrom both manufacturing and maintenance standpoints.

By virtue of the advantageous features as outlined above, the sandingdrum according to this invention meets the requirements which have longbeen unfulfilled, whereby it realizes with a simple construction asolution to the defects and problems inherent to the conventionalsanding apparatus, of either drum type or wide belt type, and whereby itencompasses the advantageous features of the two conventional typeapparatus, i.e., eliminating the problem of undesirable marks to beprinted on the finished surface of the product by the seam of thesanding surface member for use with the conventional drum type sandingapparatus, yet further enjoying advantageous features of the drumsander, such as the simple construction, low production cost, free fromthe toilsome works, etc., thus essentially promoting an efficiency andrationalization of the sanding operations. 1

The invention has been described in an illustrative manner and 'itshould be understood that the terminologies which have been used hereinare intended to be only in the nature of words of description ratherthan of limitation. Obviously, many modifications and variations of thepresent invention are possible in light of the above teachings;

surized fluid is discharged therefrom said jacket folds in a radialdirection;

a cylindrical sleeve body surrounding said jacket,

said body being made of resiliently stretchable material and having aninternal diameter larger than the diameter of the peripheral surface ofsaid base to define therebetween an annular zone in which said jacket isdisposed, said body being expanded radially outwardly when said jacketis expanded;

a seamless cylindrical sanding member separate from and surrounding saidbody and adapted to be releasably frictionally engaged with the outersurface of said body when said jacket and said body are expanded, saidsanding member being separable from said body when said jacket isfolded.

2. A sanding drum structure according to claim 1, in which said bellowsmeans comprises substantially flat, radially inner and radially outercylindrical walls interconnected by foldable side walls, said inner andouter walls defining substantially cylindrical inner and outer surfaceswith said inner surface being adapted to releasably frictionally gripthe peripheral surface of said base when said jacket is expanded; saidside walls being foldable toward each other when pressurized fluid isdischarged therefrom.

3. A sanding drum structure according to claim 2, in which said body isattached to the outer wall of said bellows means.

4. A sanding drum structure according to claim 2, in which-said body isseparate from said bellows means, said body being contacted by saidouter wall of said bellows means and being expanded radially outwardlywhen said bellows means is expanded so that said body releasablyfrictionally grips and is supported by said bellows means.

5. A sanding drum structure according to claim 1 wherein means areprovided to hermetically seal compressed air within said jacket so as tomaintain a high pressure therewithin enough to rigidly support said bodyduring sanding operations.

6. A sanding drum structure according to claim 1 wherein said body ismade of sponge rubber.

7. A sanding drum structure according to claim 1 in which said body isfree from connection to and support by said base except through saidjacket.

8. A sanding drum structure according to claim 7, in which the axialends of said body extend axially beyond the axial ends of said jacketand the axial ends of said sanding member are disposed directly radiallyoutwardly of the axial ends of said jacket.

9. A sanding drum structure according to claim I, in which said jacketcomprises a series of axially spaced, circumferentially extending jacketsections each having substantially flat inner and outer walls.

1. A sanding drum structure, comprising: a sanding drum base having asubstantially cylindrical peripheral surface; a tubular inflatablejacket surrounding said peripheral surface, said jacket comprisingradially foldable bellows means inflatable by pressurized fluid so thatwhen pressurized fluid is supplied thereto said jacket expands radiallyto snugly engage said peripheral surface of said base and to define asubstantially cylindrical outer surface, and when pressurized fluid isdischarged therefrom said jacket folds in a radial direction; acylindrical sleeve body surrounding said jacket, said body being made ofresiliently stretchable material and having an internal diameter largerthan the diameter of the peripheral surface of said base to definetherebetween an annular zone in which said jacket is disposed, said bodybeing expanded radially outwardly when said jacket is expanded; aseamless cylindrical sanding member separate from and surrounding saidbody and adapted to be releasably frictionally engaged with the outersurface of said body when said jacket and said body are expanded, saidsanding member being separable from said body when said jacket isfolded.
 2. A sanding drum structure according to claim 1, in which saidbellows means comprises substantially flat, radially inner and radiallyouter cylindrical walls interconnected by foldable side walls, saidinner and outer walls defining substantially cylindrical inner and outersurfaces with said inner surface being adapted to releasablyfrictionally grip the peripheral surface of said base when said jacketis expanded; said side walls being foldable toward each other whenpressurized fluid is discharged therefrom.
 3. A sanding drum structureaccording to clAim 2, in which said body is attached to the outer wallof said bellows means.
 4. A sanding drum structure according to claim 2,in which said body is separate from said bellows means, said body beingcontacted by said outer wall of said bellows means and being expandedradially outwardly when said bellows means is expanded so that said bodyreleasably frictionally grips and is supported by said bellows means. 5.A sanding drum structure according to claim 1 wherein means are providedto hermetically seal compressed air within said jacket so as to maintaina high pressure therewithin enough to rigidly support said body duringsanding operations.
 6. A sanding drum structure according to claim 1wherein said body is made of sponge rubber.
 7. A sanding drum structureaccording to claim 1 in which said body is free from connection to andsupport by said base except through said jacket.
 8. A sanding drumstructure according to claim 7, in which the axial ends of said bodyextend axially beyond the axial ends of said jacket and the axial endsof said sanding member are disposed directly radially outwardly of theaxial ends of said jacket.
 9. A sanding drum structure according toclaim 1, in which said jacket comprises a series of axially spaced,circumferentially extending jacket sections each having substantiallyflat inner and outer walls.